Hard line 3/8 fuel pump to carb?

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Old Mar 29, 2024 | 06:55 PM
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Hard line 3/8 fuel pump to carb?

Is SS the best material to use from mechanical fuel pump to carb? 3/8 is what I want to use. What is the best routing to go? I assume keeping as far from the engine as possible? I would of course double flare all ends. Need some input. Thanks folks!
Old Mar 29, 2024 | 06:59 PM
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I got one from Inline Tube for my 69 442 in SS, and it was spot on hard stuff to bend at home.
Old Mar 29, 2024 | 07:06 PM
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Originally Posted by eggydrummer
Is SS the best material to use from mechanical fuel pump to carb? 3/8 is what I want to use. What is the best routing to go? I assume keeping as far from the engine as possible? I would of course double flare all ends. Need some input. Thanks folks!
I just used regular old steel fuel line. Practiced on a a few scrap bits first.......Bent it up and double flared it. It's less than 10psi so you know....it's not a spaceship.

That reminds me. We originally ordered a replacement from Inline tube and it wasn't even close to fitting my 100% stock setup. Called them up and they said that I must be mistaken because it's the right one for the '66 Toronado. Well, like I said it wasn't even close. Waste of time talking to those guys. Just made a new one myself and saved the headache.

Last edited by ourkid2000; Mar 29, 2024 at 07:14 PM.
Old Mar 29, 2024 | 07:15 PM
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Originally Posted by ourkid2000
I just used regular old steel fuel line. Practiced on a a few scrap bits first.......Bent it up and double flared it. It's less than 10psi so you know....it's not a spaceship.

That reminds me. We ordered the replacement from Inline tube and it wasn't even close to fitting my 100% stock setup. Called them up and they said that I must be mistaken because it's the right one for the '66 Toronado. Well, like I said it wasn't even close. Waste of time talking to those guys.
Is there specific routine to go? I have a 61 Olds 98. I’ll post a pic of what I have mocked up temporarily until
I get a plan in place.
Old Mar 29, 2024 | 07:20 PM
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Originally Posted by eggydrummer
Is there specific routine to go? I have a 61 Olds 98. I’ll post a pic of what I have mocked up temporarily until
I get a plan in place.
I'm no expert or anything. I just used a coat hangar to make myself a little map to follow and used a cheap tube bender to bend it up. Gotta get the fittings on there before the tube ends get too bent to install them........then flare the ends and then make the final bends at the end. If it doesn't work out, cut yourself another piece and give er another go.

Cool car though! I just looked it up and I've never seen one before. Very neat car!
Old Mar 29, 2024 | 07:30 PM
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Originally Posted by ourkid2000
I'm no expert or anything. I just used a coat hangar to make myself a little map to follow and used a cheap tube bender to bend it up. Gotta get the fittings on there before the tube ends get too bent to install them........then flare the ends and then make the final bends at the end. If it doesn't work out, cut yourself another piece and give er another go.

Cool car though! I just looked it up and I've never seen one before. Very neat car!
Thanks! Here’s some pics of my “mock up”. Is this path ok? Does it matter if it’s this close to the engine?







Old Mar 29, 2024 | 07:43 PM
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I think that looks really good. Just keep about a 1/2" clearance from the engine so that you don't risk any chafing and I'd call 'er good! Double check it for leaks as well.

Some weird looking fittings on that thing, is it stock?
Old Mar 29, 2024 | 07:46 PM
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Originally Posted by ourkid2000
I think that looks really good. Just keep about a 1/2" clearance from the engine so that you don't risk any chafing and I'd call 'er good! Double check it for leaks as well.

Some weird looking fittings on that thing, is it stock?
Nope this is just temporary, they’re just compression brass fittings, not even tightened up, they will NOT be used for the final setup, this is was just to keep things in place until my 3/8 line and fittings show up. Don’t worry, I’ll double flare the connections properly.
Old Mar 30, 2024 | 08:21 AM
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Originally Posted by eggydrummer
Is SS the best material to use from mechanical fuel pump to carb?
In a word, no. At least not in my experience. The original hard line from the fuel pump to the carb was not stainless steel. Stainless looks nice and will certainly last forever, but keep in mind one thing. Stainless steel is HARDER than the OEM steel. In order for a seal to be made at the various fittings, the flared end has to deform slightly as it is tightened to fill in all of the microscopic gaps. This is not an issue for OEM steel, but it can be an issue for stainless. I actually read about this somewhere.

I replaced the fuel line on my '67 Delta 88 with a 425 engine with stainless steel, and it was difficult to get the fittings to seal. I got the line from Inline Tube, and it was pre-bent to fit my application. I'd tighten the fittings at each end to what seemed like a good tightness, start the engine, and I'd get leaks. Stop the engine, tighten some more, and restart the engine. Still leaks. I eventually ended up making the fittings VERY tight, pretty much uncomfortably so. But the fittings did ultimately seal, and I had no further problems. But if I had to do it over again, I would definitely get the OEM steel and save some money in the process.
Old Mar 30, 2024 | 08:32 AM
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Originally Posted by jaunty75
In a word, no. At least not in my experience. The original hard line from the fuel pump to the carb was not stainless steel. Stainless looks nice and will certainly last forever, but keep in mind one thing. Stainless steel is HARDER than the OEM steel. In order for a seal to be made at the various fittings, the flared end has to deform slightly as it is tightened to fill in all of the microscopic gaps. This is not an issue for OEM steel, but it can be an issue for stainless. I actually read about this somewhere.

I replaced the fuel line on my '67 Delta 88 with a 425 engine with stainless steel, and it was difficult to get the fittings to seal. I got the line from Inline Tube, and it was pre-bent to fit my application. I'd tighten the fittings at each end to what seemed like a good tightness, start the engine, and I'd get leaks. Stop the engine, tighten some more, and restart the engine. Still leaks. I eventually ended up making the fittings VERY tight, pretty much uncomfortably so. But the fittings did ultimately seal, and I had no further problems. But if I had to do it over again, I would definitely get the OEM steel and save some money in the process.
What would the OEM steel be made of? I’ll have to get some on order.
Old Mar 30, 2024 | 08:36 AM
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I don't know the grade exactly. It's a milder steel. It will work fine. It's what was originally on the car, after all.
Old Mar 30, 2024 | 08:40 AM
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This is a useful thread for me, as I am still in the process of worrying my ILT-ordered custom-bent fuel line into place. It's about an inch out in places, which is just enough to require use of a bending tool, so I'm getting psyched to try doing that without cracking it like I did the last one.

Then there's the matter of getting the fittings clocked correctly so the angles allow everything to be buttoned up.

Best of luck to OP!
Old Mar 30, 2024 | 08:42 AM
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x2 on using mild steel for the fuel line, especially if you are doing a concours restoration.
Old Mar 30, 2024 | 08:55 AM
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Originally Posted by eggydrummer
What would the OEM steel be made of? I’ll have to get some on order.
I am going to guess at this a little. 1012, 1015, 1018, or 1020 steel tubing. It would be pliable for bending and not likely to crack.
Old Mar 30, 2024 | 08:58 AM
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Originally Posted by jaunty75
I don't know the grade exactly. It's a milder steel. It will work fine. It's what was originally on the car, after all.
Not sure what the original was, I’ve had rubber line with a metal filter inline l. It’s always been with rubber lines when my gramps gave it to me after buying it from an old woman in the 90’s. Would aluminum work? Not sure which is easiest to work with. It’s only from the mechanical fuel pump to glass bowl filter to carb.
Old Mar 30, 2024 | 08:59 AM
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Another reason I'd go with original steel is alluded to by BangScreech. Even though the line I ordered was pre-bent to fit, a little tweaking was still needed to get everything to line up just right. It is easier to bend the OEM steel than it is the stainless, even just a little bit.
Old Mar 30, 2024 | 11:35 AM
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Originally Posted by eggydrummer
Not sure what the original was, I’ve had rubber line with a metal filter inline l. It’s always been with rubber lines when my gramps gave it to me after buying it from an old woman in the 90’s. Would aluminum work? Not sure which is easiest to work with. It’s only from the mechanical fuel pump to glass bowl filter to carb.
Rubber line is prone to eventually leak and that will be an instant fire , aluminum will crack from vibration. Neither is preferable material.
Old Mar 30, 2024 | 11:42 AM
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Originally Posted by 68post
Rubber line is prone to eventually leak and that will be an instant fire , aluminum will crack from vibration. Neither is preferable material.
this would suffice right?

3/8" x 25' PVF-Coated Steel Brake, Fuel, Transmission Line Tubing Coi

Old Mar 30, 2024 | 12:37 PM
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Are we overthinking this? I just went to the local auto parts store, asked if they a few feet of 3/8 steel fuel/brake line, paid for it and left. It was like 12 bucks.
Old Mar 30, 2024 | 12:42 PM
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Originally Posted by ourkid2000
Are we overthinking this? I just went to the local auto parts store, asked if they a few feet of 3/8 steel fuel/brake line, paid for it and left. It was like 12 bucks.
Ha! You may be right. KISS; keep it simple stupid righr?
Old Mar 30, 2024 | 01:40 PM
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Originally Posted by eggydrummer
Ha! You may be right. KISS; keep it simple stupid righr?
If it can handle brake line pressures it should be just fine for your fuel.......in my opinion anyway.
Old Mar 31, 2024 | 06:56 AM
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Unless you have a really high end tubing bender I’d stick to softer metal. I have a decent 5/16” 3/8” bender and I still have trouble bending Nicole/copper lines into anything past 45 degrees. I like the idea of buying a pre-bent versions. I’ll have to look into that for my Jeep.

Old Mar 31, 2024 | 08:55 AM
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Originally Posted by mb13
I like the idea of buying a pre-bent versions. I’ll have to look into that for my Jeep.
As mentioned above though, don't expect a perfect fit out of the box. It's gonna need some tweaking.
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